<p>First, the percentiles don't really matter in the scheme of things - colleges don't really look at them. Second, since they are based on the results of all students who take the exam in a particular year, it is probably impossible to predict how they might change from freshman year (when relatively few freshmen and sophomores take the exam) to junior year (when larger numbers take the exam). So, I wouldn't worry about the percentile, or worry about it too much. Focus instead on the actual scores, which is all colleges ultimately will care about in the end. Those should typically rise significantly between freshman and junior year, even without prep, as the PSAT is designed for juniors, and junior level curriculum achievement.</p>
<p>I myself think requiring students to take the PSAT every year from 9th grade on is a bit silly. I think it's fine to take it once in 10th grade for practice, or before then if it is needed for a summer program or other actual purpose, but requiring all students to take it puts too much emphasis on the test too early, in my humble opinion.</p>